The global energy consumption is increasing every day owing to the economic growth, urbanization, population growth, high standard of living and high income level. The conventional power plants cannot satisfy the world energy needs without some noticeable challenges such as greenhouse gas emissions, acid rain, health challenges, global warming, climate change and air pollution. The feasible alternative solution to meet ever increasing energy consumption in residential, commercial and industrial sectors of the economy is renewable energy sources (RESs) owing to the technical, political, societal, financial and environmental benefits. The hybrid energy system (HES) that is made up of wind turbine (WT), fuel cell (FC), photovoltaic (PV) and utility grid is proposed in the study to meet the energy needs of distinctive users in Cape Town, South Africa. The study's goal can be accomplished by making use of fmincon optimization technique to minimize the life cycle emission (LCE) of greenhouse gas (GHG), life cycle cost (LCC) and monetary value of energy purchased from the grid and maximize the job creation (JC), human development index (HDI), annual benefit (AB) and usage of PV, WT and FC. The effectiveness of the simulation technique applied in the paper can be assessed by comparing the HSE results with those from the base system. The outcomes of the HES offer a better performance with a payback period of 2.75 years, annual benefit of $329530, annual energy cost saving of $6899.3, annual electricity bill of $62747, potential energy saving of 52.37% and LCC of $419300. The annual energy purchased from the grid has reduced from 146,190 kWh to 59,593 kWh; this translates to 59.24% reduction when compared to the base system. The proposed HES with a non-renewable energy usage (NREU) of 40.78% and a renewable energy usage (REU) of 59.22% is financially feasible with a cost of energy (COE) of 0.0122 $/kWh and ecologically friendly with CO2, SO2 and NOx LCE reductions of 58.85%, 58.81% and 58.29% when compared with the base system. This indicates that PV, FC and WT can be used in the traditional power system to lower the annual electricity bill, energy purchased from the utility grid and GHG emissions. The results obtained from the assessment of the proposed HES serve as crucial decision-supporting tools that can be used by designers and operators in choosing the right parts for their power systems. The outcomes of the study can be utilized to enhance sustainability of electricity supply and minimize poverty in the developing countries.